In the past 65 years, antibiotics have been critical in the fi ght against infectious
diseases caused by bacteria. Penicillin was discovered in 1928, but it was only by
the end of the 1940s that it became generally available. This was soon followed by
the discovery and development of new antibiotics, including chloramphenicol and
tetracycline. However, shortly after the introduction of each of these new antibiotics,
resistance was detected. Nowadays, disease-causing microbes that have become
resistant to antibiotic drug therapy are a major health problem worldwide, both in
hospitals and the communit. Infections with resistant bacteria increase
the health care costs, length of hospital stay, and mortality, compared to infections
caused by bacteria that are susceptible to standard antibiotics. The problem is
particularly pressing in developing countries, where the infectious disease burden is
high and cost constraints restrict the application of newer, often more expensive and
more toxic agents.